Typically, a connector is configured such that a slight clearance is, for facilitating attachment/detachment to/from a partner connector, formed with the connector being connected to the partner connector. In the typical connector, an elastic member such as a spring is provided to close up the clearance to suppress backlash due to such a clearance. For example, in a connector described in Japanese Patent No. 5406746 (Patent Literature 1), a clearance (an engagement clearance) between a connector lock portion and a connector engagement portion can be closed up by a spring piece provided at a back wall of a fitting recessed portion.